Check valve



29, 1932- R. u. LIPSCOMB ET AL 1,839,255

CHECK VALVE Filed Aug. 7. 1931 INVENTORJ /& M 21. z

-x4e! M,

ATTORNEYS.

Patented Nov. 29, 1932 UNITED STATES PATENT OFFICE ROBERT U. LIPSCOMB AND EDWARD KUNSIdZAN, OF -E11; PASO, TEXAS CHECK VALVE Application filed August 7,1931. Serial No. 555,775.

The present invention relates to check valves of the differential piston or balanced type.

The principal object of the invention is to provide a cashioning eifect for the movements of the valves to minimize sudden actioning fluids under pressure, such as piston type,

pumps, air compressors, injectors, inspirators, piston type feed water heaters, etc., and it may be used also in the suction portion of piston type pumps. It is to be understood, moreover, that changes, within the scope of the claims hereto appended, may be made 1n the form, construction and arrangement of the several parts, without departing from the spirit of the invention.

Reference should be had to the accompan ing drawing in which boiler check embodying the invention.

Fig. 2 is a horizontal section takenon the line 2-2 of Fig. 1.

In the drawing, the reference numeral 3- designates a body, which in the illustrated form of device is of T shape. At the lower end of the body is a connecting nipple 4 secured'in place by a ground joint 5 and screw collar 6, and threaded at 7 to connect with the discharge of a feed'water pumpor 1njector, not shown. This is the inlet of the device,

The vertical portion of the body 3 communicates with the horizontal or side portipn 3 through an orifice having a valve seat 8, with which the usual shut-off valve 9 is adapt- .ed to cooperate. The space 10 within the body portion 3' is the outlet of the device, and communicates directly with the boiler mthe usual manner by means of a flanged joint 11;

Fig. 1 is a vertical central section of a- 12 is the stem for operating the shut-ofi' valve 9 when desired. When the check valve is functioning, this valve 9 is open. v

The upperend of the vertical body portion 3 carries an interior sleeve '13,. connected therewith by a ground joint 14 and screw collar 15. The interior of this sleeve is formed with two cylinders of unequal diameters, the upper cylinder lfibeing smaller than the lower cylinder 17. The upper-end of the. upper cyhnder is closed, and is preferably provided with a screw plug 18. The wall of the sleeve 13, between the upper and lower cylinders, is provided with p0rts'19, which communicate with an annular space 20 between said sleeve and the body 3.

A pair of pistons 21 and 22 connected by a, stem 23, operate in the cylinders 16 and 1'? respectively. The lower andlarger piston 22 has a valve face 24 adapted to cooperate with m a seat 25 formed in the upper end of the nipple a. This isthe check valve 'proper.- The lower end of the sleeve 13 is spaced from the seat 25', so that, when the pistons are elevated to open the valve, water can flow from the inlet 4 through the space 20, past the shutofi valve 9, and into the boiler through tlie spacelOz- Y The space 26 within the sleeve 13 between the pistons21 and 22 is open to boiler pressure through the space 20 and the ports 19. When the check valve opens by upward movement of the pistons, on account of increased pressure in the inlet 4:, water is forcekLout through'the ports 19, due to the differential efiect of said pistons. The resistance of said ports to the outward flow raises the pressure Within said space 26, thereby cushioning the opening movement of the valve, and preventing it from moving suddenly to the upper limit of its travel. When the pressure in the inlet 4 falls "and the pistons begin to move downwardly to close .the valve, the ports 19 restrict the flow of water into the expanding space 26, thereby reducing the pressure in said space and. allowing the valve to close gently. Thus hammering is minimized in both opening and closing of the valve. The space 16 above the'upper piston acts as an air 10tcushion to further prevent hammering on the upward movement of the pistons.

vice is intended for use with gases instead of liquids these ports may be made smaller than those shown. In the case of gases, the cushioning effect upon closing 0 the valve, although present to some extent, would be less than in the case of liquids.

We claim: t

1. A check valve comprising a body having an inlet," an outlet, and a valve seat therebetween; a cylinder within said body, the end portions of said cylinder having different diametersandits central portion having a restricted orifice connecting it with'said outlet; connected pistons of different effective area operable within said cylinder portions, the outer face of one piston being exposed to the pressure of said inlet and the inner faces of both pistons being exposed to the outlet pressure within said cylinder; and a valve face carried bythat piston which is exposed to the inlet pressure for cooperation with said seat. v

2. A check valve comprising a body having an inlet, an outlet, and a valve seat therebetween; a sleeve within and spaced from said body, said sleeve forming a cylinder, said cylinder having its end portions of difierent diameters and having a restricted orifice connecting'its' central portion-with said outlet; connected pistons of different effective area operable within said cylinderportions, the

outer face of one piston being exposed to the pressure of said inlet and the inner faces of both pistons being exposed to the outlet pres sure within said 0 linder; and a valve face carried by that piston which is exposed tothe inlet pressure for cooperation with said seat.

'3. A check valve comprising a body having an inlet, an outlet, and a valve seat therebetween; a sleeve within and spaced from said body, said sleeve being coaxial with said seat I and having its end spaced therefrom, and said sleeve forming a continuous chamber with cylindrical end portions of different diameters 'an'd. having its central portion in communication'with said outlet; and connected pistons of different effective area exposed to the outlet pressure and operable in said cylinder ortions, one of said pistons having a valve ace adapted for cooperation'with said seat.

4. A check valve comprising a tubular body having'an inlet at its lower end, a valve seat above said inlet, and an olitlet in its side; a sleeve within and spaced from saidbody, the 

